2. The precautionary principle

The precautionary principle (sometimes referred to as “precautionary approach”) came to prominence several decades ago. It was first formulated as an attempt to confer legal status to the notion of precaution, in order to protect the environment from potentially severe or irreversible damage in those situations of scientific uncertainty where a full risk or cost-benefit analysis was not practical (or possible). It needs to be distinguished from the notion of prevention (see Box 2.1). It has been subsequently applied to a range of other areas including public health and consumer safety.

A range of formulations, from very weak to very strong, exist for the PP. Its core elements include the need for (environmental) protection; the presence of threat or risk of serious damage; and the understanding that a lack of scientific certainty1 or inconclusive findings should not be used to avoid taking action to prevent that damage (Pinto-Bazurco, 2020[1]) (Sands, P. & Peel, J. (Eds), 2012[2]). Authors such as Wiener & Rogers propose a more constraining approach by also referring to the resulting obligation to take action in the face of uncertainty and the need to provide evidence of safety (“reverse burden of proof") (Wiener and Rogers, 2002[3]). The PP may be applied in a variety of contexts, notably related to the development of new laws and regulations, including standards; monitoring measures or licensing arrangements; and to the application of existing legislation and definition of associated legal requirements. It should be noted that outside the environmental policy area, the application of the PP is contested – but, de facto, a number of countries either apply it, or at times take policy decisions premised on a “cautious” approach, to which these findings and recommendations can apply.

To date, there is no universally accepted definition of the PP. According to Wiener, there is no single authoritative statement of the PP but rather several different precautionary principles (Wiener and Rogers, 2002[3]) (Wiener, 2016[8]). In a similar vein, academic work has identified at least 19 definitions of the PP (Sandin, 2004[9]).

Despite the absence of a single definition of the PP and the various formulations available, a number of key elements common to many of them have been outlined by the World Commission on the Ethics of Scientific Knowledge and Technology (UNESCO, World Commission on the Ethics of Scientific Knowledge and Technology, 2005[10]).2

  • The PP applies when considerable inconclusive scientific findings about causality, magnitude, probability, and nature of harm exist. It can also apply when there is a lack of agreement as to the nature or scale of the likely adverse effects of a given activity or substance.

  • The PP is not intended to apply to hypothetical effects or imaginary risk, and it should be based on a scientific examination. In addition, it will not apply to situations in which the desired level of protection is defined, and the risk of harm can be quantified. These situations can be dealt with using traditional risk management tools such as prevention.

  • In a precautionary approach, interventions are required before possible harm occurs, or before certainty about such harm can be achieved. As such (and in general terms), a wait-and-see-strategy is excluded, although active wait-and-see approaches coupled with ongoing monitoring and assessment can be part of precautionary interventions. Any interventions should be proportional to the chosen level of protection and the magnitude of possible harm (to the extent that the latter can be assessed).

  • In case of action, a wide range of initiatives may be available; e.g. measures that constrain the possibility of the harm, or measures that limit the scope of the harm and increase the controllability of the harm, should it occur.

  • There is a need for ongoing systematic empirical search for more evidence and better understanding (long-term monitoring and learning) of potential harms.

It should be noted that, given the lack of an agreed definition, a number of existing interpretations are much narrower in scope and do not encompass many of the elements presented above.

From the onset, the advent of new technologies has given rise to critical, opposing voices that herald their potential for major, possibly irreversible damage. These worries about potential harm were originally more focused on social (cultural, political) consequences, as was seen with the invention of the printing press in the 15th century and the increasingly rapid diffusion of varied, hard-to-control printed material:

Ironically, the uniformity of the copies of Gutenberg’s Bible led many superstitious people of the time to equate printing with Satan because it seemed to be magical. Printers’ apprentices became known as the "printer’s devil”. In Paris, Fust [a typographer] was charged as a witch. Although he escaped the Inquisition, other printers did not. (Waite, 2001[11])

Early technical changes leading to increased use of mined coal instead of charcoal may have lacked visibility (even though they proved, in retrospect, to have far-reaching consequences). However, the application of several combined innovations (hard coal, steam machine, cast iron production), which notably led to the introduction of steam-powered locomotives and railroad expansion in the early 19th century,3 encountered quite severe reactions warning of an impending disastrous impact on health and safety. For example, preliminary surveys for railroad construction conducted in England at the time were reported to face “strong opposition, which did not always stop at legal action and verbal attack, but in some instances led to the display of force” (Robert H. Thurston, A. M., C. E., 1878[12]).

It would be tempting to wave away the example above as being “obviously” wrong in hindsight. While critics’ predictions were indeed proven entirely misplaced in their specifics, they were arguably far less wrong in their warning that such a completely novel, radically transformative technology, which brought human civilisation to a completely new era, could have unpredictable, extremely far-reaching and potentially disastrous consequences. Indeed, this was true not only in cultural, social and political terms, but also in environmental and safety ones. Assessing the balance of positive and negative effects of the transformation is immensely difficult, and ultimately cannot be done without a value of judgment, prioritising certain outcomes over others. Railroads enabled massive improvements in agricultural productivity and food supply, with immediate positive impacts in terms of life expectancy and average wealth. However, they also contributed to a growing gap in development between different parts of the world, thereby facilitating increased imperialism, which went on to destroy millions of lives. The energy and transportation revolution (further continued with oil and the internal combustion engine) transformed human life in many ways and brought immense benefits (making humans, at least those above the poverty level, safe from death from cold and hunger, and bringing uncounted comforts to their lives). However, it has also led to environmental destruction on an unprecedented scale, to the point that runaway global warming is now a real threat (Goldblatt and Watson, 2012[13]).

This early example, even though it pre-dates the use of the “precaution” terminology, matters in many ways; the early industrial, energy and transport revolutions were criticised from many corners, and while a hundred years later these critics appeared to have been largely proven wrong, this is all far less obvious two hundred years on. This illustrates the difficulty in predicting the longer-term, large-scale impact of profoundly disruptive, transformative innovations.

Interestingly, and importantly for our research, the concerns about the health and social impacts of the industrial revolution provide another example. Many critics at the time raised the alarm about the unacceptable health and safety harms, environmental destruction, and extreme exploitation of workers (including juveniles). This was sometimes combined with a romantic view generally hostile to “unnatural” innovations (a trend also present in many of the precaution discussions today).

The gradual improvement of conditions of industrial workers and towns over more than a century provides several insights:

  • Regulation can play a role in addressing some of the harms, as exemplified by the emergence of health and safety regulation in the 19th century, and later by environmental regulation (Blanc, 2018[14]).

  • Policy changes proved indispensable to addressing the major abuses driven by extremely unequal bargaining power. Various measures included regulatory interventions and income redistribution. (UK Parliament, 2022[15]) (Moselle, 1995[16]).

  • While “in the longer term” the transformations worked largely to the benefit of most of the populations in industrialised countries, this does not mean that risks and harms could not have been managed better or addressed more effectively today. Nor, indeed, does it mean that the catastrophic longer-term, initially unpredictable consequences, are to be ignored. Many cities that relied on soft coal or fuel suffered through decades of dense air pollution (Stradling and Thorsheim, 1999[17]) and, in 2016, outdoor air pollution was estimated to cause 4.2 million premature deaths worldwide each year (World Health Organization, 2021[18]).

This example of the industrial and transport revolution illustrates that, whilst contemporary calls for “precaution” were not always justified, they did point to the fact that — in the longer run — major innovations have far more complex, far-reaching and sometimes disastrous consequences than initially predicted by their proponents. Historically closer to us, recurring environmental and health scandals have impacted public trust in new technologies and in the reassurances of “official” voices, be they scientific or governmental. These notably include the harm caused by DDT and related chemicals, the Thalidomide scandal, and the Love Canal disaster in the US (Blanc, F., Ottimofiore, G. and Macrae, D., 2015[19]) (OECD, 2010[20]).

What distinguishes the PP from both appeals to “precaution” in general, and public reactions to earlier health and environmental scandals, is its definition of a legal principle which aims to avoid disasters or lasting harm by a proactive application of precaution in a mandatory way.

Notable examples of the PP can be found in Swedish and German law. The 1969 Swedish Environmental Protection Act (Sand, 1999) stated that authorities do not have to demonstrate that a certain impact will occur, and that mere risk (if not too remote) is deemed enough to warrant protective measures or a ban on the activity. West Germany’s 1970 Clean Air Act upheld the “Vorsorgeprinzip” to help “prevent the development of harmful effects” (Wey, 1993). The PP has subsequently been recognised by some countries in their national legislation (sometimes with Constitutional status) — e.g. Belgium, France and Brazil. Regarding the energy sector, a relevant example can be found in the Netherlands. The country is currently developing a set of policy principles for safety and health in the energy transition. The current version of these principles, which are to undergo a national consultation, refers to precaution specifically, with the PP being applicable mainly to long-term health risks in contexts of relatively high uncertainty (Government of The Netherlands, Unpublished[21]). While a number of countries have included the PP in their national laws, countries across the world have taken a variety of approaches in the application of the PP, including deliberately not incorporating it into their legislation. As indicated in this report’s introduction, the findings and recommendations can be valid and useful regardless of this specific context.

In addition to being incorporated into national law by some countries, the PP was increasingly used in international and EU-level instruments from the 1990s onwards. Key milestones in this respect include the 1992 Rio Declaration on Environment and Development, representing the multilateral recognition of the PP, and the 1998 Wingspread Statement, i.e. an academic definition of the PP.4 These illustrate the variety of PP formulations: the Rio Declaration is stated in the negative (uncertainty should not preclude preventive action), whereas the Wingspread Statement imposes an affirmative obligation to act notwithstanding uncertainty (Mossman, K.L. and Marchant, G.E., 2002[22]).

At the EU level, the PP was enshrined in the Maastricht Treaty in 1992 and it is now included in Article 191 of the Treaty on the Functioning of the European Union. However, the PP is not defined in the either treaty. It states: “Union policy on the environment shall aim at a high level of protection considering the diversity of situations in the various regions of the Union. It shall be based on the precautionary principle and on the principles that preventive action should be taken, that environmental damage should as a priority be rectified at source and that the polluter should pay.” Hence, through the Maastricht Treaty, the PP acquired constitutional status. It was formally articulated by the European Commission’s Communication on the Precautionary Principle (see Box 2.2), which was subsequently endorsed by the Council of Ministers (Nice Resolution). The Communication states that: “The precautionary principle applies where scientific evidence is insufficient, inconclusive or uncertain and preliminary scientific evaluation indicates that there are reasonable grounds for concern that the potentially dangerous effects on the environment, human, animal or plant health may be inconsistent with the high level of protection chosen by the EU.”5

For more details, Löfstedt provides an analysis of the evolution of policymakers’ use of the PP over time (Lofstedt, 2003[23]), and authors including Klinke and Renn provide an overview of risk reduction activities derived from the PP’s application (Klinke and Renn, 2002[24]).

Interpretation of the PP has continued to evolve in recent decades. In the EU, the PP is argued to have evolved from being associated with a “better safe than sorry” perspective, to being identified with “reversed burden of proof(Lofstedt, 2004[25]). In 2004, Lofstedt concluded that, at EU level, the “pendulum” may have been swinging back from precaution and harm prevention towards approaches based on risk assessment (Lofstedt, 2004[25]) (Wiener and Rogers, 2002[3]). However, there have been examples of precautionary approaches in recent years suggesting that this trend is not so clear-cut (Lofstedt, 2011[26]) (Lofstedt et al., 2011[27]) (Lofstedt and Bouder, 2017[28]).

Annex A presents selected examples of the integration of the PP into national and international law. Annex B showcases international examples and experience regarding the application of the PP and risk-based regulation, including in the energy sector.

As reminded by Wiener, the PP remains controversial. The author quotes Marchant & Mossman (2004):

The precautionary principle may well be the most innovative, pervasive, and significant new concept in environmental policy over the past quarter century. It may also be the most reckless, arbitrary, and ill-advised. (Wiener, 2018[37]) (Wiener, 2018, citation of Marchant & Mossman,2004).

While it is beyond the scope of this paper to describe the full range of arguments for and against the precautionary principle, a summary of the main ones is presented below. Subsequent sections of this report elaborate further upon a number of these arguments.

Proponents of the PP highlight its usefulness in preventing potentially severe (and sometimes irreversible) harms stemming from hazard sources for which there is insufficient scientific evidence:

  • Precautionary measures (early and anticipatory) can help address the risks of latent impacts, i.e. those that do not occur until long after their causes (climate change being a prime example) (Wiener, 2018[37]).

  • The PP can encourage more open discussion of the value judgements underpinning methods of risk assessment and cost-benefit analysis (Stirling, 2016[38]).

  • It may help to avoid situations in which standard risk analysis otherwise creates a bias in favour of taking chances on poorly understood risks (Grant & Quiggin, 2013, quoted in (European Commission, 2017[6]).

  • PP can be used as a decision-making rationale that incorporates concerns for distributional effects (equity), which can complement appraisal methodologies that quantify the benefits and costs of a proposed, activity, such as cost-benefit analysis (Sadeleer, 2012[39]). Related to this are various examples of outcomes that the PP may potentially help avoid (see Box 2.3).

Critics of the PP as a tool for decision-making tend to point at the existence of multiple interpretations, leading to inconsistent application (including risks of the PP being invoked “casually”), and its potentially deterring effect on innovation:

  • Since it is not well-defined, the PP can undermine legal certainty. In addition, it is subject to a number of psychological biases.

  • Consistently applied, evidence-driven risk-based regulation already foresees ways to deal with uncertain risks, potential major hazards with low or uncertain probability, in a proportionate way (IRGC, 2017[42]) (OECD, 2021[43])

  • It can stifle innovation, particularly if applied rigidly (see Chapter 3, “The PP and innovation: How well do they mix?”) – and thus clash with other key policy principles and priorities (OECD, 2021[44]).

  • It could negatively affect world trade and international regulatory co-operation (Bailey, 1999[45]) (Hannesson, 2014[46]). Moreover, unwarranted recourse to the PP may be a disguised form of protectionism.

  • There is insufficient guidance on the level of precaution to adopt in practice, or the level of scientific information needed to trigger the exercise of the PP.

  • Gemmell and Scott argue that, while the PP was deployed “as a justification both for greater care and for the operator to prove the harm would be managed”, there has been too casual and unsubstantiated reliance on it, as well as an overly prescriptive approach to activity and process detail rather than on outcomes. This, they argue, has been a real weakness (Gemmell, J. Campbell; Scott, E. Marian, 2013[47]) and often led to a political backlash against “excessive burden”. Given the importance of this aspect, this report seeks to provide recommendations on how the original spirit and intent of the PP can be effectively “reactivated”, moving away from overly rigid “all-or-nothing” or “no-by-default” approaches.

  • It is not applied consistently, thus leading to “unprincipled” decision-making; e.g. Wiener’s EU-US comparative analysis concludes that both jurisdictions were selective in the use of the precautionary principle, with neither consistently more precautionary than the other (Wiener and Rogers, 2002[3]); Garnett and Parsons’ case studies (EU and case law) conclude that:

The decision whether or not to apply the precautionary principle appears to be poorly defined, with ambiguities inherent in determining what level of uncertainty and significance of hazard justifies invoking it (Garnett, K. and Parsons, D. J., 2017[48]).

Chapter 3 discusses and elaborates on some of the notions and key arguments outlined so far. It draws on select, relevant applications of the PP, their associated challenges, and how the PP is articulated between notions of uncertainty, hazard, risk and precaution.


[49] Aven, T. (2006), “On The Precautionary Principle, In The Context of Different Perspectives on Risk”, Risk Management, Vol. 8/3, pp. 192-205, https://doi.org/10.1057/palgrave.rm.8250010.

[45] Bailey, R. (1999), Precautionary Tale, https://reason.com/archives/1999/04/01/precautionary-tale/.

[19] Blanc, F., Ottimofiore, G. and Macrae, D. (2015), Understanding and addressing the Risk Regulation Reflex, https://www.researchgate.net/publication/276949964_Understanding_and_addressing_the_Risk_Regulation_Reflex.

[14] Blanc, F. (2018), From Chasing Violations to Managing Risks, Edward Elgar Publishing, https://doi.org/10.4337/9781788112499.

[50] Buchanan, R. A. et al (2022), “Steam locomotive”, Britannica, https://www.britannica.com/technology/history-of-technology/Space-age-technology.

[8] Cinnamon Carlarne, K. (ed.) (2016), Precaution and Climate Change, Oxford Univ. Press.

[29] EPRS (2015), The Precautionary principle. Definitions, applications and governance., https://www.europarl.europa.eu/RegData/etudes/IDAN/2015/573876/EPRS_IDA(2015)573876_EN.pdf.

[6] European Commission (2017), Future brief: The precautionary principle: decision-making under uncertainty.

[36] European Commission (2000), Communication from the Commission on the precautionary principle, Commission of the European Communities, COM(2000) 1 Final, https://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=COM:2000:0001:FIN:EN:PDF.

[41] European Environment Agency (2011), Late lessons from early warnings:, https://www.eea.europa.eu/publications/environmental_issue_report_2001_22/Issue_Report_No_22.pdf/view.

[48] Garnett, K. and Parsons, D. J. (2017), Multi-Case Review of the Application of the PrecautionaryPrinciple in European Union Law and Case Law, https://onlinelibrary.wiley.com/doi/epdf/10.1111/risa.12633.

[47] Gemmell, J. Campbell; Scott, E. Marian (2013), Environmental regulation, sustainability and risk.

[13] Goldblatt, C. and A. Watson (2012), “The runaway greenhouse: implications for future climate change, geoengineering and planetary atmospheres”, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 370/1974, pp. 4197-4216, https://doi.org/10.1098/rsta.2012.0004.

[4] Gollier C., and Triech, N. (2003), Decision-Making under Scientific Uncertainty: The Economics of the Precautionary Principle, pp. 77-103, https://econpapers.repec.org/RePEc:kap:jrisku:v:27:y:2003:i:1:p:77-103.

[21] Government of The Netherlands (Unpublished), Verantwoord omgaan met veiligheid en gezondheid in de energietransitie. Uitgangspunten voor beleid, vergunningverlening, communicatie en toezicht.

[32] Graham, J. and S. Hsia (2002), “Europe’s precautionary principle: Promise and pitfalls”, Journal of Risk Research, Vol. 5/4, pp. 371-390, https://doi.org/10.1080/1366987021058580.

[46] Hannesson, R. (2014), Ecofundamentalism: a Critique of Extreme Environmentalism, Lexington Books.

[7] International Risk Governance Council (2006), Risk Governance, Towards an Integrative Approach.

[42] IRGC (2017), Introduction to the IRGC Risk Governance Framework, revised version, EPFL International Risk Governance Center, https://doi.org/10.5075/epfl-irgc-233739.

[24] Klinke, A. and O. Renn (2002), “A New Approach to Risk Evaluation and Management: Risk‐Based, Precaution‐Based, and Discourse‐Based Strategies<sup>1</sup>”, Risk Analysis, Vol. 22/6, pp. 1071-1094, https://doi.org/10.1111/1539-6924.00274.

[26] Lofstedt, R. (2011), “Risk versus Hazard – How to Regulate in the 21<sup>st</sup> Century”, European Journal of Risk Regulation, Vol. 2/2, pp. 149-168, https://doi.org/10.1017/s1867299x00001033.

[25] Lofstedt, R. (2004), The Swing of the Regulatory Pendulum in Europe: From Precautionary Principle to (Regulatory) Impact analysis.

[23] Lofstedt, R. (2003), “The Precautionary Principle”, Process Safety and Environmental Protection, Vol. 81/1, pp. 36-43, https://doi.org/10.1205/095758203762851976.

[31] Löfstedt, R. (2014), “The precautionary principle in the EU: Why a formal review is long overdue”, Risk Management, Vol. 16/3, pp. 143-145, https://doi.org/10.1057/RM.2014.7.

[28] Lofstedt, R. and F. Bouder (2017), “Evidence-based uncertainty analysis: What should we now do in Europe? A view point”, Journal of Risk Research, Vol. 24/5, pp. 521-540, https://doi.org/10.1080/13669877.2017.1316763.

[27] Lofstedt, R. et al. (2011), “The changing nature of communication and regulation of risk in Europe”, Journal of Risk Research, Vol. 14/4, pp. 409-429, https://doi.org/10.1080/13669877.2011.557479.

[33] Majone, G. (2002), “What price safety? The precautionary principle and its policy implications”, Journal of Common Market Studies, Vol. 40/1, pp. 89-109, https://doi.org/10.1111/1468-5965.00345.

[35] Mcnelis, N. (2000), “EU Communications on the precautionary principle”, Journal of International Economic Law, Vol. 3/3, pp. 545-551, https://academic.oup.com/jiel/article/3/3/545/829423 (accessed on 14 April 2023).

[16] Moselle, B. (1995), “Allotments, Enclosure, and Proletarianization in Early Nineteenth-Century Southern England”, The Economic History Review, Vol. 48/3, https://www.jstor.org/stable/2598178.

[22] Mossman, K.L. and Marchant, G.E. (2002), The Precautionary Principle and Radiation Protection.

[5] Nerhagen, L., S. Forsstedt and K. Edvardsson (2018), “The precautionary principle and regulatory impact assessment: on the need for initial screening of hazards in regulatory work with examples from transport”, Working papers in Transport Economics, No. 2018:14, CTS - Centre for Transport Studies Stockholm (KTH and VTI), http://www.cts.kth.se (accessed on 19 April 2023).

[43] OECD (2021), OECD Regulatory Policy Outlook 2021, OECD Publishing, Paris, https://doi.org/10.1787/38b0fdb1-en.

[44] OECD (2021), Recommendation of the Council for Agile Regulatory Governance to Harness Innovation. OECD/LEGAL/0464.

[20] OECD (2010), Risk and Regulatory Policy: Improving the Governance of Risk, OECD Reviews of Regulatory Reform, OECD Publishing, Paris, https://doi.org/10.1787/9789264082939-en.

[40] Patterson, A. and T. Gray (2012), “Unprincipled? The British government’s pragmatic approach to the precautionary principle”, Environmental Politics, Vol. 21/3, pp. 432-450, https://doi.org/10.1080/09644016.2012.671573.

[1] Pinto-Bazurco, J. (2020), The Precautionary Principle, https://www.iisd.org/articles/precautionary-principle.

[12] Robert H. Thurston, A. M., C. E. (1878), The Growth of the Steam-engine, https://web.archive.org/web/20120214185756/http://www.history.rochester.edu/steam/thurston/1878/.

[39] Sadeleer, N. (ed.) (2012), Implementing the Precautionary Principle, Routledge, https://doi.org/10.4324/9781849771696.

[9] Sandin, P. (2004), The Precautionary Principle and the Concept of Precaution, pp. 461-475, https://www.jstor.org/stable/30302022.

[2] Sands, P. & Peel, J. (Eds) (2012), Principles of international environmental law, Cambridge University Press.

[38] Stirling, A. (2016), Precaution in the Governance of Technology. SPRU Working Paper Series, https://www.researchgate.net/publication/305986930_Precaution_in_the_Governance_of_Technology_SWPS_2016-14/link/57a874da08ae0107eee467f3/download.

[17] Stradling, D. and P. Thorsheim (1999), “The Smoke of Great Cities: British and American Efforts to Control Air Pollution, 1860–1914”, Environmental History, Vol. 4/1, pp. 6-31, https://doi.org/10.2307/3985326.

[15] UK Parliament (2022), Poverty and the Poor Law, https://www.parliament.uk/about/living-heritage/transformingsociety/livinglearning/19thcentury/overview/poverty/.

[10] UNESCO, World Commission on the Ethics of Scientific Knowledge and Technology (2005), The Precautionary Principle.

[30] Vos, E. and K. De Smedt (2020), RECIPES, WP1 Report: Taking stock as a basis for the effect of the precautionary principle since 2000, https://recipes-project.eu/sites/default/files/2021-01/Report_Taking%20stock%20as%20a%20basis%20for%20the%20effect%20of%20the%20precautionary%20principle%20since%202000_Final.pdf.

[11] Waite, J. (2001), The Unsung Heroes, a History of Print, https://web.tech.uh.edu/digitalmedia/materials/3350/religion_and_print.html.

[37] Wiener, J. (2018), “Precautionary Principle”, Chapter VI.13, pp.174-185 in volume 6 on Principles of Environmental Law (Ludwig Kramer and Emanuela Orlando, eds.) of the Encyclopedia of Environmental Law (Michael Faure, ed.) (IUCN and Edward Elgar, 2018),, https://www.elgaronline.com/view/nlm-book/9781786436986/b-9781785365669-VI_13.xml.

[3] Wiener, J. and M. Rogers (2002), Comparing precaution in the United States and Europe, pp. 317-349.

[18] World Health Organization (2021), Ambient (outdoor) air pollution, https://www.who.int/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health.

[34] Zander, J. (2010), The Application of the Precautionary Principle in Practice, Cambridge University Press, https://doi.org/10.1017/cbo9780511779862.


← 1. Lack of scientific certainty is understood as any kind of instance in which if the scientific findings are inconclusive, have large errors, or come with unacceptable uncertainties to policymaking.

← 2. For an overview of academic discussion around the scientific foundations and justification of the PP, the reader may notably refer to (Aven, 2006[49]) and (Klinke and Renn, 2002[24]).

← 3. Experiments combining use of the steam locomotive and a permanent travel way of metal rails culminated in the Stockton & Darlington Railway, opened in 1825; the Liverpool and Manchester Railway, which opened in 1830, constituted the first fully timetabled railway service with scheduled freight and passenger traffic relying entirely on the steam locomotive for traction (Buchanan, R. A. et al, 2022[50]).

← 4. The Wingspread Consensus Statement on the Precautionary Principle was made following a three-day academic conference involving lawyers, policymakers and environmentalists.

← 5. Lofstedt reports that in the period 1994 to 1999, the term “precautionary principle” was referred to in 27 European Parliament resolutions (Lofstedt, 2004[25]).

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